System and method for operating a communications system

ABSTRACT

A method ( 500, 600 ) is provided of operating a local transceiver ( 300 ), comprising: setting the local transceiver into an operational mode; operating the local transceiver in a polling mode ( 520 ); receiving a quiescent begin indicator identifying a beginning of a quiescent mode ( 520 ); setting a portion of the local transceiver into a low power consumption mode in response to the quiescent begin indicator ( 540 ); measuring an elapsed time since receiving the quiescent begin indicator as a quiescent time ( 530, 550 ); and returning the portion of the local transceiver to the operational mode based on a quiescent end indicator  550, 580, 690 ).

FIELD OF THE INVENTION

The present invention relates in general to a system and method foroperating a communications network that allows for a temporary quiescentperiod to save power and reduce unnecessary interference on acommunications channel.

BACKGROUND OF THE INVENTION

In any network in which devices share a single transmission channel(e.g., a wireless network, a shared bus network, etc.), every device canhear all or most of the other devices. In such a network when twodevices transmit a signal at the same time, the two transmitted signalsare considered to have collided, which can cause those signals to becomeunintelligible, meaning no data is sent, and thus the use of thetransmission medium (i.e., the transmission channel) is lost for a time.Both signals will then have to be resent, lowering the data throughputof the network. If this happens often enough, the entire transmissionmedium could be rendered ineffective. It's therefore typically desirableto avoid, or at least minimize, such collisions.

One way to accomplish this is to accept the existence of collisions andtry and minimize their occurrence or their effect through the use of acollision-based protocol. A collision-based protocol allows multipledevices to transmit data when they need to without any prearrangement.For example, an ALOHA protocol allows each device to transmit data whenit wishes without monitoring the channel at all. In this protocol, fatalcollisions simply prompt a retransmission. This results in comparativelyhigher collision rates and reduced efficiency as more transmissions mustbe resent. A slotted ALOHA protocol further refines the idea by dividingthe available transmission time up into discrete time slots. It uses anALOHA protocol within those time slots, but only allows each device tostart a transmission at the beginning of one of the time slots. Thus, ifno collision occurs immediately, it won't happen at all. And a carriersense multiple access (CSMA) protocol requires a potential transmittingdevice to listen to the transmission channel prior to transmitting, andonly allows it to transmit if it hears no one else transmitting (i.e.,only if the transmission channel is clear).

Another way to reduce or eliminate collisions is to use a time divisionmultiple access (TDMA) protocol, in which a network coordinator (ormaster device) restricts the use of the channel to one network device(or slave device) at any given time. A time slotting TDMA protocoldivides the available transmission time up into discrete time slots andassigns them to individual devices or device pairs. Each device can onlytransmit in its allotted time, but knows that it won't have a collisionwith another device. A polling TDMA protocol does not assign specifictime slots to each device, but rather has a network coordinatorperiodically poll each device in the network to see if it has data tosend. The network coordinator can then assign channel time to eachdevice based on its response to the poll.

A polling protocol allows great flexibility in allocating the availablechannel time. However, it incurs an overhead cost in that the networkcoordinator must repeatedly poll each device in the network to see ifthey have data to send. This can be particularly wasteful if no devicein the network has any data to send. In such a case, the networkcoordinator will continually transmit polling signals, and the deviceswill repeatedly have to respond, when neither side has anything new tosay.

A polling protocol can therefore create unnecessary signal traffic on alimited transmission medium that may well be shared with other networks.For example a wireless network may operate proximate to other wirelessnetworks. Concurrent transmission in each network may require thenetworks to take steps that increase signal quality at the cost oftransmission speed. This may be acceptable when each network istransmitting data, but is wasteful when one network is simplytransmitting unnecessary polling signals.

In addition, a polling protocol forces power-limited devices to keeptheir receivers on for extended periods of time, listening for pollingsignals even when no one in the network has any data to send. This cancause unnecessary drain on battery power, and can be particularly bad indevices in which the receiver circuitry represents a significant portionof the power consumption of the device. For example, ultrawide bandwidthdevices typically have complex and power-hungry receivers that employ alarge amount of signal processing because the transmission signals arebelow the noise floor. Such devices experience significant power drainany time their receiver is turned on.

It is therefore desirable to provide a system and method for datatransmission in a communications network in which collisions can beminimized, but in which unnecessary transmissions by a networkcoordinator are also minimized.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying figures where like reference numerals refer toidentical or functionally similar elements and which together with thedetailed description below are incorporated in and form part of thespecification, serve to further illustrate an exemplary embodiment andto explain various principles and advantages in accordance with thepresent invention.

FIG. 1 is a message sequence chart of a communications network enteringa quiescent mode according to disclosed embodiments;

FIG. 2 is a state diagram of network operation according to disclosedembodiments;

FIG. 3 is a block diagram of a network transceiver according todisclosed embodiments of the present invention;

FIG. 4 is a flow chart of the operation of a network coordinatoraccording to disclosed embodiments;

FIG. 5 is a flow chart of the operation of a network device according todisclosed embodiments in which polling requests are allowed during aquiescent mode; and

FIG. 6 is a flow chart of the operation of a network device according todisclosed embodiments in which contention-based transmissions areallowed during a quiescent mode.

DETAILED DESCRIPTION

The current disclosure is provided to further explain in an enablingfashion the best modes of performing one or more embodiments of thepresent invention. The disclosure is further offered to enhance anunderstanding and appreciation for the inventive principles andadvantages thereof, rather than to limit in any manner the invention.The invention is defined solely by the appended claims including anyamendments made during the pendency of this application and allequivalents of those claims as issued.

It is further understood that the use of relational terms such as firstand second, and the like, if any, are used solely to distinguish onefrom another entity, item, or action without necessarily requiring orimplying any actual such relationship or order between such entities,items or actions. It is noted that some embodiments may include aplurality of processes or steps, which can be performed in any order,unless expressly and necessarily limited to a particular order; i.e.,processes or steps that are not so limited may be performed in anyorder.

Much of the inventive functionality and many of the inventive principleswhen implemented, are best implemented in integrated circuits (ICs). Itis expected that one of ordinary skill, notwithstanding possiblysignificant effort and many design choices motivated by, for example,available time, current technology, and economic considerations, whenguided by the concepts and principles disclosed herein will be readilycapable of generating such ICs with minimal experimentation. Therefore,in the interest of brevity and minimization of any risk of obscuring theprinciples and concepts according to the present invention, furtherdiscussion of such ICs, if any, will be limited to the essentials withrespect to the principles and concepts used by the exemplaryembodiments.

Polling and Quiescent Operation

One way to minimize both collisions and unnecessary transmissions by anetwork coordinator is to provide a polling protocol in which TDMApolling is performed during a polling mode, but can be stopped for aperiod of time during a quiescent mode. This allows the network toreduce or eliminate collisions by using the polling mode when thedevices in the network have data to send, but then to reduce unnecessarytransmissions and power consumption by using the quiescent mode when thenetwork has little or no network traffic to send. In order to provideadequate control for the quiescent mode, a timer can be used to providecoordination between a network coordinator and devices in the network.

FIG. 1 is a message sequence chart of a communications network enteringa quiescent mode according to disclosed embodiments. As shown in FIG. 1,operation begins in a polling mode when a master device 105 (i.e., anetwork coordinator or network controller) sends a polling signal 120 toa slave device 110 (i.e., a non-coordinating device in the network).

The slave device 110 then responds by sending a data signal 125, sinceit has data to send. In this example, the data signal 125 is sent to themaster device 105. However once the polling signal 120 is given, theslave device 110 would typically be allowed to send its data signal 125to any device in the network. In some embodiments the slave device 110may also pass some queue data to the master device 105 (e.g., indicatingthe type of data it has to send, how much total data it has to transmit,etc.).

After the slave device 110 is finished with its data transmission 125,the master device 105 then sends a polling signal 130 to the slavedevice 115 to see if it has data to send. In this example, the slavedevice 115 responds to the polling signal 130 by sending a data signal135 to the master device 105. Again, the slave device 115 wouldtypically be allowed to send its data signal to any device in thenetwork, and may also pass some queue data to the master device 105.

The master device 105 then continues the polling mode by again sending apolling signal 120 to the slave device 110. In this case, however, theslave device 110 has no data to send. Therefore, instead of sending adata signal to a target device, it sends a null acknowledgement (NAK)signal 145 to the master device 105 indicating that it has no data tosend. In some embodiments this NAK signal 145 can also provide anindication of how long the slave device 110 expects to not have data.

After receiving the NAK 145 from the slave device 115, the master device105 continues the polling mode by again sending a polling signal 130 tothe slave device 115. In this case, the slave device 115 sends a datasignal 135 to the slave device 110.

The master device 105 then continues the polling mode by sending anotherpolling signal 120 to the slave device 110. And this time the slavedevice 115 has no additional data to send, so it sends a NAK signal 155to the master device 105 indicating no data to send.

At this point the master device 105 knows that there is no data to betransmitted in the network, and so sends a broadcast shutdown signal 160to all of the slave devices 110, 115 indicating they should enter into aquiescent mode. This quiescent mode will last at most for a certainperiod of time (i.e., a quiescent time), and ends when the master device105 sends a new polling signal 120 to the slave device 110.

During the course of the polling mode, the master device 105 repeatedlypolls each of the devices in the network. In some embodiments it can bean even polling scheme in which each device is polled equally. In otherembodiments it can be an uneven polling scheme in which some devices arepolled more often than others. In some embodiments the master device 105may base the polling frequency of each network device on information itknows regarding each device (e.g., the streaming nature of data sentfrom each device, information it receives from the devices regarding howbig their transmit queues are, etc.)

Although not shown in FIG. 1, if the master device 105 is also a networkdevice, it can also allocate channel time for itself. However, since themaster device 105 coordinates the channel time, there is no need for itto send itself a separate polling signal. Rather, it can simply transmitdata to another device during its assigned portion of the channel time.

Furthermore, although in the embodiment of FIG. 1, a NAK signal 145, 155is used to indicate no data to send, alternate embodiments can use othersignal types to indicate that a slave device 110, 115 has no data tosend.

In addition, while in the example of FIG. 1, the master device 105stopped polling each slave device 110, 115 after they indicated oncethey had no data, alternate embodiments can require a slave device 110,115 to respond multiple times that it has no data before the masterdevice 105 will consider it ready for a quiescent mode. Alternatively,the master device 105 could base this decision on queue informationreceived from each slave device 110, 115.

Although in FIG. 1, every polling signal 120, 130 receives a response ofsome kind from one of the slave devices 110, 115, it is possible that insome cases the master device 105 will not receive a response. Forexample, a slave device 110, 115 might be shut off, have left the areaof the network, or simply not hear the polling signal 120, 130. Themaster device 105 may be configured to wait only a set time-out periodbefore considering the polling signal a failure and proceeding to thenext slave device.

As shown in FIG. 1, during operation, the network can shift betweenpoling and quiescent modes (or states). The various devices 105, 110,and 115 control their state of operation through the use ofmode-changing triggers.

FIG. 2 is a state diagram of network operation according to disclosedembodiments. As shown in FIG. 2, the network operates in one of twomodes, a polling mode 210 and a quiescent mode 220.

In the polling mode 210, a network coordinator (e.g., a master device105) repeatedly sends polling signals 120, 130 to devices in the network(e.g., slave device 110, 115), who only transmit data in response to thepolling signals.

In the quiescent mode 220, the network coordinator does not send anypolling signals 120, 130, and one or more of the devices in the networkmay enter into a power-saving mode.

The network transitions from the polling mode 210 to the quiescent mode220 based on a quiescent trigger. The quiescent trigger for the networkcoordinator may be each device responding with a NAK a certain number oftimes in a row (which number may be one), each device specificallyindicating within a response to the network coordinator that it has nodata to send, or any other suitable indicator. Alternate embodiments canalso have the quiescent trigger be some external signal. For example,the quiescent trigger may be a request from a co-located network thatwishes to have the channel cleared for a certain period of time. Undercertain circumstances (e.g., when the network has little or no data tosend, or at least no time-critical data to send), the network may acceptsuch an external request as a quiescent trigger.

The quiescent trigger (or indicator) for the network devices willtypically be a signal from the network coordinator indicating entry intothe quiescent mode. However in some embodiments a network device mayconsider it a valid quiescent indicator if it goes a certain period oftime without receiving a polling signal. In such an embodiment thenetwork coordinator does not have to specifically send a broadcastshut-down signal 160, but can simply stop sending polling requests.

The network transitions from the quiescent mode 220 to the polling mode210 based on a polling trigger. For the network coordinator, thispolling trigger may be the passing of a certain amount of time in thequiescent mode, the receipt by the network coordinator of a pollingrequest from one of the devices in the network, a need on the part ofthe network coordinator to send data to a device in the network, or anyother suitable indicator. For a network device, this polling trigger maybe the passing of a certain amount of time in the quiescent mode, or thereceipt by the network device of a polling signal from the networkcoordinator.

Network Transceiver

FIG. 3 is a block diagram of a network transceiver according todisclosed embodiments of the present invention. As shown in FIG. 3, thetransceiver 300 includes a receiver circuit 310, a transmitter circuit320, a switch 330, an antenna 340, an enable circuit 350, and a timer360.

The receiver circuit 310 receives incoming signals from the antenna 340and extracts information from the incoming signals, including controldata and data in. The receiver circuit 310 passes the control data tothe enable circuit 350, and the data in to additional circuitry (notshown) connected to the transceiver 300.

The transmitter circuit 320 sends outgoing signals to the antenna 340for transmission, embedding control data and data out into theseoutgoing signals. The transmitter circuit 320 receives the control datafrom the enable circuit 350, and the data out from additional circuitry(not shown) connected to the transceiver 300.

The switch 330 is placed between the antenna 340, the receiver circuit310, and the transmitter circuit 320, and is configured to connect oneof the receiver circuit 310 and the transmitter circuit 320 to theantenna based on switch control signals received from the enable circuit350. Alternate embodiments can eliminate the switch 330, however. Insome cases the transceiver 300 can use alternate means to isolate thereceiver circuit 310 and the transmitter circuit 320; in others it maynot be necessary to isolate the receiver circuit 310 and the transmittercircuit 320 at all.

The antenna 340 is configured to send and receive signals using whatevertransmission scheme is appropriate to the transceiver 300. It isconnected to the receiver circuit 310 and the transmitter circuit 320,either directly or through the switch 330.

The enable circuit 350 receives control data from the receiver circuit310 that is extracted from the incoming signals, provides control datato the transmitter circuit 320 for transmission in outgoing signals,provides the transmitter and receiver enable signals to the receivercircuit 310 and the transmitter circuit 320, provides a switch controlsignal to the switch 330, and coordinates the operation of the timer360. The enable circuit 350 also monitors the various signals itreceives for the polling and quiescent triggers.

The timer 360 is used by the enable circuit to mark the passage of thequiescent time. This can be implemented as any suitable form oftime-keeping circuit that can mark the passage of a specific period oftime.

During a polling mode, the receiver circuit 310 extracts pollinginformation from incoming polling signals and provides them to theenable circuit 350 via the control data. The enable circuit 350 thenmonitors the polling information and controls the operation of thereceiver circuit 310 and the transmitter circuit 320 accordingly.

During a quiescent mode, the enable circuit 350 monitors the quiescentmode's duration via the timer 360. The enable circuit may also instructthe receiver circuit 310 and/or the transmitter circuit 320 to go into alow-power mode (or even shut down) for some or all of the quiescentmode.

In some embodiments, the quiescent mode may allow data to be transmittedwithin the network via another protocol (e.g., a contention-basedprotocol), or may allow network devices to request that the networkcoordinator end to the quiescent mode before the end of the quiescenttime. In this case, the enable circuit may also continue to monitor thecontrol data from the transmitter circuit 320, indicating any data outthat needs to be transmitted. In some embodiments in which the receivercircuit 310 is not powered down, the enable circuit may also continue tomonitor the control data from the receiver circuit 310, to see if anydata in has been received during the quiescent mode.

Although FIG. 3 discloses a wireless transceiver 300, this is by way ofexample only. In alternate embodiments the transceiver 300 could be awired transceiver, using copper or fiberoptic wires. In such anembodiment the antenna 340 can either be removed or replaced with anappropriate wired interface element. Furthermore, the wirelesstransceiver 300 could be an RF wireless system, an optical free spacesystem, or any other appropriate wireless system.

In particular, a transceiver is provided, comprising: a transmittercircuit configured to transmit outgoing data signals in a communicationsnetwork; a receiver circuit configured to receive incoming data signalsin the communications network; a timer configured to measure an elapsedtime of a quiescent mode; and an enable circuit configured to controloperation of the transmitter circuit and the receiver circuit, and toplace the receiver circuit in a low power mode during a quiescent mode,wherein the enable circuit uses the elapsed time to determine when thetransceiver is in the quiescent mode.

The transceiver may further comprise an antenna connected to thetransmitter circuit and the receiver circuit, and configured to transmitthe outgoing data signals over a wireless transmission medium, and toreceive the incoming data signals from the wireless transmission medium.In this case, the transceiver may further comprise a switch configuredto connect the antenna to one of the transmitter circuit and thereceiver circuit based on a switch control signal received from theenable circuit.

The transceiver may be implemented in a semiconductor device.

Method of Operating a Network Coordinator

FIG. 4 is a flow chart of the operation of a network coordinatoraccording to disclosed embodiments. As shown in FIG. 4, the networkcoordinator begins by operating according to a polling scheme or pollingprotocol (410).

During this polling mode the network coordinator continually orperiodically looks for a quiescent begin trigger indicating an entryinto a quiescent mode (420). The quiescent begin trigger could bereceiving indications from all devices in the communications networkthat there is no data to be transmitted, e.g, passing through a setnumber of polling cycles without any data being sent. The quiescentbegin trigger could also be receiving specific queue information fromall the devices in the communications network that there is a certainminimum amount of data, none of which is time-critical, e.g., via queueinformation sent in a NAK signal. The quiescent begin trigger could alsobe receiving a request for quiescent mode from a source external to thecommunications network. For example, an adjacent network might make arequest to the network coordinator that it enter a quiescent mode for atime so that the adjacent network can more easily or quickly send somecritical information. If the communications network did not have anycritical data of its own to send, it might accept the external requestin order to be a good neighbor.

If the network coordinator does not receive the trigger to enter thequiescent mode (420), it returns to operating according to the pollingscheme (410), and monitoring for the quiescent mode trigger (420).

However, if the network coordinator does receive the trigger to enterthe quiescent mode (420), it starts a timer (430) and begins to operatethe network according to a quiescent scheme or a quiescent protocol(440). The quiescent scheme could be a total shutdown of the network, achange to a different transmission protocol (e.g., a contention-basedprotocol such as ALOHA, slotted ALOHA, carrier sense multiple access,IEEE 802.11 type, or the like), or a partial shutdown with sometransmissions allowed under a different protocol.

In some embodiments it may be permissible for the network coordinator toreturn the network to the polling scheme if it has data to send to anetwork device. In such a case, the network coordinator continually orperiodically determines whether it has data to send to a device in thenetwork (450). If the network coordinator does have data to send to anetwork device, it returns to the polling mode and again operates thenetwork according to a polling scheme (410). If, however, the networkdevice has no data to send, processing continues in the quiescent mode.

In some embodiments the network coordinator may maintain informationregarding which network devices continue to listen for signals duringthe quiescent mode. In this case, the network coordinator may also makea further determination regarding whether a target device for the datais listening or not. In this case, the network coordinator will onlyreturn to the polling mode (410) if the device will be listening.

In some alternate embodiments, however, it will not be permissible forthe network coordinator to exit the quiescent mode simply because it hasdata to send to a network device. In such a case, this operation (450)can be eliminated.

In some embodiments it may be permissible for the network coordinator toreturn the network to the polling scheme if it receives a pollingrequest by a network device during the quiescent mode. In such a case,the network coordinator continually or periodically determines whetherit has received a polling request from any of the network devices (460).If the network coordinator has received such a polling request, itreturns to the polling mode and again operates the network according toa polling scheme (410). If, however, the network device has received nopolling request, processing continues in the quiescent mode. Thisoperation (460) can be eliminated in some alternate embodiments in whichthe network coordinator cannot end the quiescent period early.

In many embodiments the elapsing of a set time period in the quiescentmode will represent a maximum length of the quiescent mode. This willallow devices that do enter a low-power mode to know when to return to apolling mode without having to receive any external signals. In such anembodiment, the network coordinator continually or periodicallydetermines whether it the quiescent mode has lasted for the entirequiescent time yet. (470). If it determines that the quiescent time hasended, the network coordinator returns to the polling mode and againoperates the network according to a polling scheme (410). If, however,the network coordinator determines that the quiescent time has notended, it continues to operate the network in the quiescent mode (440).

In one exemplary embodiment the maximum quiescent time may be in therange of 20-100 millisecond. However, this is simply by way of example,the maximum quiescent time can vary widely by embodiment, and may bechosen based on any number of network parameters.

In addition, in some embodiments the timing of the quiescent period(operations 430 and 460) may be eliminated altogether. For example, in anetwork in which no device enters a power conservation state during thequiescent mode, the quiescent mode might last until either the networkcoordinator or one of the network devices requested that it end.

In the embodiments of FIG. 4, operations 450 and 460 might end thequiescent mode before the expiration of the quiescent time. This leadsto the possibility that some network devices may still be in a low powermode and unable to hear any new polling signals sent out. In this case,the network may have to operate without all of its network devices beingturned on. But if it has some devices operating, it can still pass somedata.

Although operations 450, 460, and 470 are shown as being done in aparticular order, this is by way of example only, and should not beconsidered limiting. In various embodiments these determinations can bedone in any order, and can even be done in parallel.

In particular, a method of operating a network coordinator for acommunications network is provided, comprising: operating the networkcoordinator in a polling mode; identifying a quiescent begin triggerindicating a start of a quiescent mode; operating the networkcoordinator in the quiescent mode after identifying the quiescent begintrigger; measuring an elapsed time since receiving the quiescent begintrigger as a quiescent time; and returning to operating the networkcoordinator in the polling mode based on a quiescent end indicator.

The quiescent begin trigger may be one of: receiving indications fromall devices in the communications network that there is no data to betransmitted, receiving queue information from all the devices in thecommunications network that there is a certain minimum amount of data,none of which is time-critical, and receiving a request for quiescentmode from a source external to the communications network.

The quiescent end indicator may be one of: the quiescent time reaching amaximum quiescent duration, the network coordinator receiving a pollingrequest, and the network coordinator identifying data to be sent to aremote device in the communications network. In particular, thequiescent end indicator may be the quiescent time reaching the maximumquiescent duration if the network coordinator does not receive thepolling request before the quiescent time reaches the maximum quiescentduration, and the network coordinator does not identify data to be sentto the remote device before the quiescent time reaches the maximumquiescent duration.

The operating of the network coordinator in the polling mode maycomprise: sending a polling signal over a transmission medium to apolled device chosen from a plurality of network devices; allocatingsufficient channel time after the sending of the polling signal for thefirst network device to make a response to the polling signal; andrepeating the operations sending and allocating a plurality of times,wherein the response to the polling signal is one of: sending a datatransmission to a target device chosen from the plurality of networkdevices; or sending an acknowledgement signal to the network coordinatorindicating that the polled device has no data to be sent, wherein eachrepetition of the operations of sending and allocating may change to anew polled device, and wherein each repetition of the operations ofsending and allocating may change to a new target device.

The communications network may be a wireless network. And the method maybe implemented in a semiconductor device.

Method of Operating a Network Device

FIG. 5 is a flow chart of the operation of a network device according todisclosed embodiments in which polling requests are allowed during aquiescent mode. As shown in FIG. 5, the network device begins byoperating according to a polling scheme or polling mode (510).

During this polling mode the network device continually or periodicallylooks for an indicator (or trigger) to enter a quiescent mode (520). Thequiescent begin indicator could be receiving a mode change signal (e.g.,a shutdown signal) from the network coordinator; or it could be simplynot receiving a polling signal for a certain period of time.

If the network device does not receive the indicator to enter thequiescent mode (520), it returns to operating according to the pollingscheme (510) and monitoring for the quiescent mode indicator.

However, if the network device does receive the indicator to enter thequiescent mode (520), it starts a timer (530), enters into the quiescentmode (540) and begins to operate the network according to a quiescentscheme or a quiescent protocol. The quiescent mode could be a totalshutdown of the device, a change to a different transmission protocol(e.g., a contention-based protocol such as ALOHA, slotted ALOHA, carriersense multiple access, IEEE 802.11 type, or the like), or a partialshutdown of the device with some processing continuing during thequiescent mode.

In many embodiments the elapsing of a set time period in the quiescentmode will represent a maximum length of the quiescent mode. This willallow devices that do enter a low-power mode to know when to return to apolling mode without having to receive any external signals. In such anembodiment, the network device continually or periodically determineswhether the quiescent mode has lasted for the entire quiescent time yet.(550). If it determines that the quiescent time has ended, the networkdevice returns to the polling mode and again operates according to apolling scheme (510). If, however, the network coordinator determinesthat the quiescent time has not ended, processing continues.

If the quiescent time has not passed (550), the network devicecontinually or periodically determines whether it has any data to send(560). If it does not have any data to send, the network device returnsto determining whether the quiescent time has ended (550).

If, however, the network device does have data to send, it sends apolling request to the network coordinator (470), and then determineswhether it has received a polling signal (480).

If the network device has received a polling signal, then it returns tothe polling mode and operates itself according to the polling schemeagain (510). If, however, it does not receive a polling signal within anacceptable amount of time, it simply returns to determining whether thequiescent time has elapsed (550) and considers the polling request afailure. In various embodiments the network device may attempt to sendanother polling request at a later time during the quiescent mode, ormay simply wait until the quiescent mode ends and a new polling signalis received before trying to send the data.

Although operations 550 and the combination of operations 560 through580 are shown as being done in a particular order, this is by way ofexample only, and should not be considered limiting. In variousembodiments these determinations can be done in any order, and can evenbe done in parallel.

FIG. 6 is a flow chart of the operation of a network device according todisclosed embodiments in which contention-based transmissions areallowed during a quiescent mode. The operation of a network deviceaccording to FIG. 6 is the same as according to FIG. 5, except for howthe network device handles the situation where it has data to sendduring a quiescent mode.

In FIG. 6, operations 510, 520, 530, 540, 550, and 560 are performed asdescribed above with respect to FIG. 5.

In this embodiment, however, if the network device determines that itdoes have data to send (560), it simply sends the data using acontention policy (690), without asking permission from the networkcoordinator. And when the data is sent using the contention policy, thenetwork device returns to monitoring whether the quiescent time haselapsed (550). In alternate embodiments it may be possible to use adifferent transmission policy during the quiescent mode, aside from apolling protocol or a contention-based protocol.

Although operations 550 and the combination of operations 560 through690 are shown as being done in a particular order, this is by way ofexample only, and should not be considered limiting. In variousembodiments these determinations can be done in any order, and can evenbe done in parallel.

In addition, although FIGS. 5 and 6 show two alternate ways of a networkdevice handling data to be transmitted that comes up during thequiescent mode, alternate embodiments could combine the two. Forexample, a network device could first send a polling request to transmitthe data, and then, if that received no response, send the data using analternate protocol, or vice versa.

In particular, a method of operating a local transceiver is provided,comprising: setting the local transceiver into an operational mode;operating the local transceiver using a polling protocol in theoperational mode; receiving a quiescent begin indicator identifying abeginning of a quiescent mode; setting a portion of the localtransceiver into a low power consumption operation in response to thequiescent begin indicator; measuring an elapsed time since receiving thequiescent begin indicator as a quiescent time; and returning the portionof the local transceiver to the operational mode based on a quiescentend indicator. The portion of the local transceiver may be a receiverportion.

The portion of the local transceiver may be turned off during the lowpower consumption operation. The quiescent end indicator may be thequiescent time reaching a maximum quiescent duration. The quiescent endindicator may also be the local transceiver identifying data to be sentto a remote transceiver.

The method may further comprise operating the local transceiver usingthe polling protocol after the quiescent time reaches the maximumquiescent duration.

The method may further comprise: sending a polling request to a networkcoordinator after the local transceiver identifies data to be sent, butbefore the quiescent time reaches a maximum quiescent time; andoperating the local transceiver using the polling protocol after sendingthe polling request.

The method may further comprise: operating the local transceiver using acontention protocol after returning the receiver to the operationalmode, but before the quiescent time reaches a maximum quiescent time;and operating the local transceiver using the polling protocol after thequiescent time reaches the maximum quiescent time. The contentionprotocol may be one of: an ALOHA protocol, a slotted ALOHA protocol, anda carrier sense multiple access protocol.

The operating of the local transceiver using a polling protocol maycomprise: monitoring a transmission medium for a polling request;receiving the polling request identifying the local transceiver andindicating a set of transmission parameters for the transceiver; sendingdata over the transmission medium based on the set of transmissionparameters if the local transceiver has data to send; sending a signalover the transmission medium indicating that there is no need for datatransmission if the local transceiver has no data to send; and repeatingthe operations of monitoring, receiving, sending data, and sending thesignal a plurality of times.

The local transceiver may be a wireless transceiver. And the method maybe implemented in a semiconductor device.

Conclusion

This disclosure is intended to explain how to fashion and use variousembodiments in accordance with the invention rather than to limit thetrue, intended, and fair scope and spirit thereof. The foregoingdescription is not intended to be exhaustive or to limit the inventionto the precise form disclosed. Modifications or variations are possiblein light of the above teachings. The embodiment(s) was chosen anddescribed to provide the best illustration of the principles of theinvention and its practical application, and to enable one of ordinaryskill in the art to utilize the invention in various embodiments andwith various modifications as are suited to the particular usecontemplated. All such modifications and variations are within the scopeof the invention as determined by the appended claims, as may be amendedduring the pendency of this application for patent, and all equivalentsthereof, when interpreted in accordance with the breadth to which theyare fairly, legally, and equitably entitled. The various circuitsdescribed above can be implemented in discrete circuits or integratedcircuits, as desired by implementation.

1. A method of operating a local transceiver, comprising: setting thelocal transceiver into an operational mode; operating the localtransceiver using a polling protocol in the operational mode; receivinga quiescent begin indicator identifying a beginning of a quiescent mode;setting a portion of the local transceiver into a low power consumptionoperation in response to the quiescent begin indicator; measuring anelapsed time since receiving the quiescent begin indicator as aquiescent time; and returning the portion of the local transceiver tothe operational mode based on a quiescent end indicator.
 2. The methodof claim 1, wherein the portion of the local transceiver is a receiverportion.
 3. The method of claim 1, wherein the portion of the localtransceiver is turned off during the low power consumption operation. 4.The method of claim 1, wherein the quiescent end indicator is thequiescent time reaching a maximum quiescent duration.
 5. The method ofclaim 3, further comprising operating the local transceiver using thepolling protocol after the quiescent time reaches the maximum quiescentduration.
 6. The method of claim 1, wherein the quiescent end indicatoris the local transceiver identifying data to be sent to a remotetransceiver.
 7. The method of claim 6, further comprising: sending apolling request to a network coordinator after the local transceiveridentifies data to be sent, but before the quiescent time reaches amaximum quiescent time; and operating the local transceiver using thepolling protocol after sending the polling request.
 8. The method ofclaim 6, further comprising: operating the local transceiver using acontention protocol after returning the receiver to the operationalmode, but before the quiescent time reaches a maximum quiescent time;and operating the local transceiver using the polling protocol after thequiescent time reaches the maximum quiescent time.
 9. The method ofclaim 8, wherein the contention protocol is one of: an ALOHA protocol, aslotted ALOHA protocol, and a carrier sense multiple access protocol.10. The method of claim 1, wherein the operating the local transceiverusing a polling protocol comprises: monitoring a transmission medium fora polling request; receiving the polling request identifying the localtransceiver and indicating a set of transmission parameters for thetransceiver; sending data over the transmission medium based on the setof transmission parameters if the local transceiver has data to send;sending a signal over the transmission medium indicating that there isno need for data transmission if the local transceiver has no data tosend; and repeating the operations of monitoring, receiving, sendingdata, and sending the signal a plurality of times.
 11. The method ofclaim 1, wherein the local transceiver is a wireless transceiver. 12.The method of claim 1, wherein the transmission medium is an opticalmedium.
 13. The method of claim 1, wherein the method is implemented ina semiconductor device.
 14. A method of operating a network coordinatorfor a communications network, comprising: operating the networkcoordinator in a polling mode; identifying a quiescent begin triggerindicating a start of a quiescent mode; operating the networkcoordinator in the quiescent mode after identifying the quiescent begintrigger; measuring an elapsed time since receiving the quiescent begintrigger as a quiescent time; and returning to operating the networkcoordinator in the polling mode based on a quiescent end indicator. 15.The method of claim 14, wherein the quiescent begin trigger is one of:receiving indications from all devices in the communications networkthat there is no data to be transmitted, receiving queue informationfrom all the devices in the communications network that there is acertain minimum amount of data, none of which is time-critical, andreceiving a request for quiescent mode from a source external to thecommunications network.
 16. The method of claim 14, wherein thequiescent end indicator is one of: the quiescent time reaching a maximumquiescent duration, the network coordinator receiving a polling request,and the network coordinator identifying data to be sent to a remotedevice in the communications network.
 17. The method of claim 14,wherein the quiescent end indicator is the quiescent time reaching themaximum quiescent duration if the network coordinator does not receivethe polling request before the quiescent time reaches the maximumquiescent duration, and the network coordinator does not identify datato be sent to the remote device before the quiescent time reaches themaximum quiescent duration.
 18. The method of claim 14, wherein theoperating of the network coordinator in the polling mode comprises:sending a polling signal over a transmission medium to a polled devicechosen from a plurality of network devices; allocating sufficientchannel time after the sending of the polling signal for the firstnetwork device to make a response to the polling signal; and repeatingthe operations sending and allocating a plurality of times, wherein theresponse to the polling signal is one of: sending a data transmission toa target device chosen from the plurality of network devices; or sendingan acknowledgement signal to the network coordinator indicating that thepolled device has no data to be sent, wherein each repetition of theoperations of sending and allocating may change to a new polled device,and wherein each repetition of the operations of sending and allocatingmay change to a new target device.
 19. The method of claim 14, whereinthe communications network is a wireless network.
 20. The method ofclaim 14, wherein the communications network is an optical network. 21.The method of claim 14, wherein the method is implemented in asemiconductor device.
 22. A transceiver, comprising: a transmittercircuit configured to transmit outgoing data signals in a communicationsnetwork; a receiver circuit configured to receive incoming data signalsin the communications network; a timer configured to measure an elapsedtime of a quiescent mode; and an enable circuit configured to controloperation of the transmitter circuit and the receiver circuit, and toplace the receiver circuit in a low power mode during a quiescent mode,wherein the enable circuit uses the elapsed time to determine when thetransceiver is in the quiescent mode.
 23. The transceiver of claim 22,further comprising an antenna connected to the transmitter circuit andthe receiver circuit, and configured to transmit the outgoing datasignals over a wireless transmission medium, and to receive the incomingdata signals form the wireless transmission medium.
 24. The transceiverof claim 23, further comprising a switch configured to connect theantenna to one of the transmitter circuit and the receiver circuit basedon a switch control signal received from the enable circuit.
 25. Thetransceiver of claim 23, wherein the transceiver is implemented in asemiconductor device.